* {
box-sizing: border-box;
}

body {
background-color: yellow;
padding: 50px;
min-height: 100vh;
display: flex;
flex-direction: column;
justify-content: center;
margin: 0;
}

.outer {
background-color: orange;
padding: 50px;
display: flex;
justify-content: center;
}

.inner {
background-color: red;
width: 200px;
height: 200px;
}